The LTC3456 is a multiple output DC/DC converter that runs off 2-cell AA batteries, USB, or an AC wall adapter. It is designed for mobile devices, including MP3 players, portable GPS units, digital cameras, and handheld computers.
This document is a design note (DN-1006) detailing the application of the LTC3456 integrated circuit. The device is described as a low-profile total power management solution optimized for confined spaces in mobile devices such as MP3 players, portable GPS units, digital cameras, and handheld computers.
The LTC3456 manages power flow between an AC adapter, USB cable, and a 2-cell AA battery while complying with USB power standards. It generates two separate regulated power rails: a fixed 3.3V main supply and an adjustable 1.8V core supply. The document includes circuit diagrams showing how to configure the device for various input sources and provides efficiency graphs and load transient response data.
| Main Supply Voltage | 3.3V (fixed) |
|---|---|
| Core Supply Voltage | 1.8V (adjustable) |
| Package Type | 4mm x 4mm 24-pin QFN |
| Switching Frequency | 1MHz constant frequency |
| Core Output Current | 200mA |
| Main Output Current | 150mA |
It supports an AC adapter, USB cable, and a 2-cell AA battery.
Efficiency reaches 93% at the higher load currents when powered by a 2-cell alkaline.